to discretely (like a ninja) tuck an erection under the waistband of underwear or belt line of pants.

a true ninja swipe is done in one swift motion.
yo, i was freeballing in my sweats when i got a boner- i had to ninja swipe that shit so it wouldn't look like i was proppin a tent
by princealberto July 7, 2009
Get the ninja swipe mug.